Firefox 55.0

What's new in this version:

- Export Screenshots 10.5.0 to Firefox
- Fix eslint warnings in about:webrtc
- Allow Flash to create Secure Socket connections
- Ensure pixels for Android dynamic toolbar snapshot get processed even if the toolbar is not visible so pending animations may run
- Backed out changeset 4488424e14ae for causing Bug 1377802
- Check if bookmarking UI is visible before anchoring bookmarking popup. This also avoids flushing when bounds checking the identity popup for visibility
- Disable frames() timing function using a pref on release/beta channels
- Part 3: Don't use restricting SIDs when running from a network drive
- Part 2: Add option to Windows chromium sandbox policy to not use restricting SIDs
- Part 1: Back out changesets 04edb03fb817 and d17ac655cc51
- Catch exception to handle creating media session fail. The crash reason is that our package name [1] is not the same as the name from packageManager's getPackagesForUid(uid) [2].Not sure what causes it and how it happen, but we can catch this exception first to avoid the crash
- Set CSP on freshly created nullprincipal when iframe is sandboxed
- Fix leak of nursery memory
- Only set user's SID in USER_LIMITED as deny only when not using restricting SIDs
- Disable H2 origin extension on Gecko 55
- Bump security preload information expiration dates to 2017-11-14 for Firefox 55
- Skip browser_toolbarbutton_menu_context.js for frequent failures
- Hold strong refs to elements when calling various functions that can run script
- Convert exception messages from the requests module before logging them
- Part 3: Require fallible Init method rather than infallible constructor when using fallible allocator
- Part 2: Deserialize StructuredCloneBlob in segments rather than a single large allocation
- Part 1: Initialize all members when using an inherited constructor
- Null-check result from GetTextRun in nsRubyBaseContainerFrame
- Add context-fill-opacity to back-large.svg
- Stop sending max-message-size
- Block D3D11 on more crashy nvwgf2um.dll versions
- Update follow-on search add-on to 0.9.1 - fix double reporting and fix case sensitivity
- Fix broken automatic HAR logs exported
- MutableBlobStorage always returns a temporary-file Blob if the size of data is greater than 1mb
- Change search settings redirects to General section of about:preferences
- Key cached manifest and locale data by add-on version
- Look for text run boundary based on transformed text when needed
- Nest ShellContext lifetime within JSContext
- Avoid null pointer deref
- Fix vertical scrollbar
- Post: remove unused code
- Guard against a nullable cursor
- Allow Adjust campaign ID to behave as OTA distribution
- Add reftest for verifying onVRPresentChange
- Don't honor the idle period during shutdown
- Add missing #include for MOZ_THREAD_LOCAL
- Support multi-line stub installer footer text
- Early return from timeline render if destroy was called
- Remove delay rendering add-on permissions popup header
- Part 2: Set initial tab title to URL's hostname until we know the actual page title
- Part 1: Add test for about: pages' initial tab titles
- repack betas are broken bc mock can't find python
- linux 55.0 repack betas are broken in comparing locales because due to missing python executable.r=aki a=testing a=jorgk
- Enable flash plugin preferences even when set to 'Never Activate'
- Sign the dummy webextension used in ts_paint_webext so that it doesn't run afoul of addon signing restrictions on Beta
- repack betas are broken bc mock can't find python, balrog.py fix
- linux 55.0 repack betas are broken in comparing locales because due to missing python executable
- Enable flash plugin preferences even when set to 'Never Activate'
- Change app.update.staging.enabled preference to false on Windows to disable update staging
- Better check of the buffer size in WebSocket
- Request an even longer timeout for browser_noopener.js
- Manage TabGroup::IsBackground passively to avoid Runnable overhead
- repack betas are broken bc mock can't find python, balrog.py fix
- Backed out changeset 68d491c00355 from bug 1329355 to temporarily fix bug 1372698
- Backed out changeset 318f1bcd336e from bug 1329355 to temporarily fix bug 1372698
- Tighten up mtime checking test_update.js